Improvement in steam-pump valve-gears



UNITED STATES PATENT .GEFICE.

BENJAMIN s. LAWSON, OE NEW YORK, N. Y.,

IMPRCVEMENT `lN STEAM-PUMP VALVE-GEARSL Specification forming partofLetters Patent No. 186,5134, dated January 23, 1877; application filedTo allwhong t may concern: Y

Be it known that I, BENJAMTN S. LAWSON, ot' New York city, in the Stateof New York,

have invented certainnew and useful Improvements relating toSteam-Pumps, of which the following is a specification:

The pump is ofthe direct-actin g class, where the pump-piston andsteam-piston are, practically, parts of the same reciprocating mass.

The improvements lie in the means for throw- Y .control the movement ofthe lever which' operated the valve.

I find the crank may be dispensed with, and

have devised means wherebyl obtain a prompt and reliable movement of thevalve without any such incum brance. I have wrought out the inventionwith devices to insure that the valve will be thrown to the properextent before the piston has moved far, in case the spring isinsufficient to induce the proper extent of motion; and I have providedmeans for restraining the action of the spring, so as to prevent itsacting beyond the proper limit in case it shall, as is usually the factwith a new spring, have more than the proper amount of force.

The accompanying drawing forms a part of this specification, and is aside elevation. The

pistons are to the left. The valve-lever is shown in the dotted line inthe position to which it is thrown by the spring so `soon as the pumphas passed the center. The strong line shows the position in which it isheld a moment previous.

Referring to the drawing, A is the ifixed framing and cylinders. Bis thepiston-rod, extending through from the steam-cylinder to the pump, thesteam-cylinder being at the left. On the piston-rod B is keyed a part,B', which extends down, and is guided in a longitudinal slot in theframing A, and also extends up- December 23, 1876.

wardand carries a cam, P, formed as represented. lhis cam is incapableot'auy motion but a direct reciproeation with the pistons.

` The valve-stem E is connected to the arm D3,

and reciprocatesV by the rocking of the lever, thereby working a valve,(shown in dotted lines,) which performs its usual functions. A

center or pivot bolt, b, is n xed in the side of the part B', to whichare knuckled two levers. The lever H travels smoothly backward andforward, being guided on the framing A, and forms simply a support orshoe for a spring, I. A lever, J1 J2, is also knuckled on the pivot-boltb, which is capable of a slight rocking motion. The long arm J1 isforced upward by the spring I. The short arm J 2 serves simply as a stopto prevent the other arm, J1, from being thrown too high. The arm J1 ndsa smooth bearing against the under face of the lever D1 D2, beingrounded (or, if preferred in any case, provided with a shoe) toaccommodate the bearing to the changing angle of the lever against whichit rocks.

As the part B' and its connections traverse alternately to the right andthe left, the bearing of the lever J1 against the lever D1 Dz changesits position from end to end. As it approaches either end of its stroke,the corresponding end of the lever D1 D2 is pressed upward. The cam Prestrains its motion, and

forbids any movement until the pistons have completed thir stroke. Thenthe side projection (which will be understood is on the end of the armD1) is liberated by having passed beyond the end of the cam P; and theparts, being thus set free, are thrown by the force of the spring'I,acting through the arm J1, and the valve-stem E is movedto change theposition of the steam-valve. In case the throw thus effected is notquite complete, as is indicated by the dotted lines in the figure, and

only a partial opening ofl the steam-valve is effected, the commencementof the motion of the pistons will bring the part p of the cam P intoaction, and thus carry the arm D1 up or down, as the case may be, to itsfull proper extent.

necessary in ordinary cases.

the cam P which holds the parts against be- In case the motion resultingfrom the action of the spring I should, instead of thus being toolittle, be in any case too much, and should tend to throw the parts toofar, the contact of the arm J2 against the adjacent portion of the partH arrests the movement.

Various modifications may be made in the forms and proportions of' theparts without defeating the objects of the invention. Variousrefinements may be added- 21s, for example, a screw may be insertedthrough the arm J2, to adjust the point at which the rise of the arm J1under a too forcible action of the spring I shall be arrested. A rollermay be provided on the side projection on the arm D1, to form a rollingcontact, rather than a sliding one, with the cam; but I do not believean)T such That portion oi' ing thrown too early is designated p. It maybe of the form represented, exactly parallel to the piston-rod, with arounded corner; or it may be further rounded; or variously modied,solong as it holds the valve againstbeing thrown too early.

I claim as my inventionlhe spring I and cam P p, each traversed asspecified, in combination with a rocking lever traversed and operated bythe joint action of the'spring and cam, and with the lever J1 J2,connectedv valve-rod E, and the cylinders and pistons of a steam-pump,as and i'or the purposes herein specified.

In testimony whereof I have hereunto set' luy-hand this 20th day ofDecember, 1876, in the presence of two subscribing witnesses.

BENJAMIN S. LAWSON.

Witnesses:

THOMAS D. SrETs'oN, GHAs. G. STETsoN.

